1. Field of the Invention
The present invention relates to a reciprocating or oscillating sprinkler device for dispersing pressurized water for plant life. More particularly, the present invention relates to a sprinkler device having a reciprocating piston which is driven by the pressure of the water coupled to a helical track on a shaft of a sprinkler head such that the reciprocal linear motion of the water driven piston is converted to a reciprocating rotational motion of the head, thereby dispersing the water.
2. Prior Art
Automatic, underground sprinkler systems have been used for many years as an easy way to dispense water over plant life, such as lawns, gardens, and flower beds. These systems have a plurality of sprinklers, or sprinkler heads, disposed about the area to be watered. The sprinklers are located to provide even coverage of the area and conserve water. In addition, these sprinklers are grouped together in zones. A network of underground pipes couples together each sprinkler in a zone. These zones, or group of sprinklers, are coupled to a main water line by a valve manifold comprising a plurality of valves, one for each zone. The valves are electrically coupled to a timer which is programed to actuate the valves at a desired time and for a desired duration.
These sprinklers typically seek to achieve a number of common, important goals, namely water conservation, even coverage or even spay patterns, ease of use, and reliability. Conservation of water is usually achieved by sprinkler and sprinkler system designs which disperse water only on the desired vegitation, such as the lawn, as opposed to walkways and driveways. Water is also conserved by nozzle designs which do not mist or spray water too high so that it is carried away by the wind. Even coverage is usually achieved by sprinkler and sprinkler system designs which disperse water evenly so that there are no dry spots or puddles.
Reliability is often difficult to achieve. Simple sprinklers, with few components and few moving parts, have fewer components to fail, but may not obtain the desired performance features, such as even spray patterns or spray distance. More complex sprinklers have better performance characteristics, such as more even coverage and further spray distances, but also have more parts to fail.
Many different types of sprinklers have been devised for dispersing water over plant life. Many of these sprinklers utilize the water itself for operating the motion of the sprinkler. These sprinklers have evolved over time from simple devices to more complex devices. Some sprinklers utilized the pressure of water to elevate a portion of the sprinkler having a nozzle out of the ground, and the weight of the elevated portion to return it into the ground. Other sprinklers were designed with springs to return the nozzle into the ground. "Impact heads" were developed which used a weighted arm, swung by the force of the water, to turn the head as the arm returns, and complicated switching devices to repeatedly alter the direction of the head. "Gear drives" were developed which used the movement of the water through the head to turn an impeller, which in turn was coupled to a number of gears to turn the nozzle.
One disadvantage with some of these sprinklers, such as impact heads and gear drives, is that their moving parts may become clogged by debris in the water. In addition, they have many parts which means more components subject to failure. For example, the gear drive has numerous gears in which debris may be lodged, stopping the head. As another example, the swing arm of the impact head, or its switch mechanism, may become caked with dirt, impeding the motion of the head.
Another disadvantage with some of these sprinklers, such as gear drives, is that they may not be disassembled or serviced. Because of the many components in these sprinklers, they are often manufactured such that they may not be disassembled for servicing. For example, the many gears and turbines in a gear drive sprinkler are often disposed in a housing which is glued or sonic welded together, which prevents opening the housing and access to the components. Another disadvantage with these sprinklers is their cost. The complexity makes them more expensive to replace.
The problem with reliability is aggravated by the typical location of the sprinkler in the ground and surrounded by dirt and sod. If a sprinkler fails, the sod and dirt surrounding the sprinkler often must be removed to uncouple the sprinkler from the system. With the sprinkler removed, dirt easily accumulates around pipe threads of the system and is introduced into the pipes forming the system. Replacing the sprinkler is difficult because the dirt must be cleared from the pipe threads. In addition, the dirt now in the pipe may clog the new sprinkler.
Other sprinklers have been proposed which use the pressure of the water to drive a system for dispensing the water. U.S. Pat. No. 4,509,686, issued Apr. 9, 1985, to Larsen, the same inventor of the present invention, discloses a piston slidably disposed in a housing. A rack and pinion is coupled between the piston and the housing to rotate the housing with a nozzle therein. This sprinkler advantageously utilizes the pressure of the water to drive the reciprocating piston and convert the linear motion of the piston to rotation motion of the nozzle. Despite this advantage, the need for simpler, more reliable sprinklers exists.
Other sprinklers have been proposed. For example, U.S. Pat. No. 5,048,758, issued Sep. 17, 1991, to Jackerson, and U.S. Pat. No. 5,107,717, issued Apr. 28, 1992, to Jackerson, disclose a sprinkler with a piston slidably disposed in a housing. A barrel type indexing cam is formed integrally with the piston. The cam has staggered, opposing triangular shapes formed thereon defining similar staggered, opposing recesses. A pin is formed in the housing and extends into the recess. As the piston, and thus the cam, moves up and down, the pin abuts the triangular shape forcing the cam, and thus the piston to rotate. The piston is rotatably fixed with respect to a shaft on which is disposed a nozzle.
U.S. Pat. No. 4,895,305, issued Jan. 23, 1990, to Powell, discloses a piston slidably disposed in a housing. A rack and pinion system is disposed between the piston and a nozzle to rotate the nozzle. U.S. Pat. No. 3,567,127, issued Mar. 2, 1971, to Raumaker et al., discloses a fixed piston in a head which moves up and down. As the head moves downwardly, an annular row of teeth formed on the head contact an annular row of inclined rubber fingers to impart slight partial rotation to the head.
Many of these sprinklers suffer from the same disadvantages as gear drive or impact heads in that they have numerous moving parts which are subject to failure or clogging. Another disadvantage with many of these sprinklers is that they rotate the nozzle in a series of discrete steps, as opposed to a continuous even motion. The result is uneven coverage and possible dry spots and puddling.
Another disadvantage with many of these sprinklers is that they dispense a main stream of water at a distance away from the sprinkler while neglecting the area immediately adjacent and surrounding the sprinkler. Thus, a plurality of sprinklers must be grouped together so that they overlap.
Another disadvantage is that they may not operate at low water pressures. Some of the sprinklers include springs which necessitate a minimum amount of water pressure in order to overcome the force of the spring. Another disadvantage with some of these sprinklers is that their operating speed, or rate of rotation, may not be adjusted.
Therefore, it would be advantageous to develop a sprinkler capable of evenly dispensing water over a large area. It would also be advantageous to develop a sprinkler with fewer parts to fail and assemble, and fewer moving parts to become clogged. It would also be advantageous to develop a sprinkler capable of smooth, continuous motion, and even coverage. It would also be advantageous to develop a sprinkler capable of operating over a range of water pressures, including low pressure. It would also be advantageous to develop a sprinkler capable of adjustable speed or rate of rotation.